1. Field of the Invention
The present invention relates to a hermetic rotary compressor, and more particularly to a discharge valve for selectively opening/closing a discharge port through which the refrigerant is discharged.
2. Description of the Prior Art
Generally, a compressor, as shown in FIG. 1, has a sealed casing 10, a motor 20 installed inside the casing 10, and a cylinder assembly 30 for compressing the sucked refrigerant while rotating under a driving force transmitted from the motor 20.
The motor 20 has a stator 21, a rotor 22, and an eccentric shaft 23. The stator 21 is press-fitted to an inner peripheral surface of the casing 10, while the rotor 22 is rotatably installed inside the stator 21 at a predetermined radial spacing therefrom. The rotor 22 is fixed with the eccentric shaft 23.
A cylinder assembly 30 includes upper and lower flanges 31 and 32 for supporting the eccentric shaft 23, a cylinder 33 installed between the upper and the lower flanges 31 and 32, and a rotor 34 mounted on the eccentric shaft 23. An inner peripheral surface of the cylinder 33 defines a compression space. The rotor 34 revolves within the compression space in accordance with the movement of the eccentric shaft 23.
A discharge port 31a is formed in the upper flange 31 so as to discharge the refrigerant which is compressed in the compression space of the cylinder 33 to a discharge space 10a of the casing 10. Additionally, a discharge valve 40 is installed at the upper flange 31. The discharge valve 40 opens the discharge port 31a under the pressure of the compression space.
As shown in FIG. 2, the discharge valve 40 has a valve member 41 and a valve backer 42. The valve member 41 is pivotably fixed to a side of the upper flange 31. The valve backer 42 limits the upward stroke of the valve member 41.
In the conventional hermetic rotary compressor, as the rotational force from the motor 20 is transmitted to the rotor 34, the rotor 34 revolves within the inner space of the cylinder 33, i.e., the compression space. Accordingly, the refrigerant is compressed in the compression space, and discharged to the discharge space 10a through the discharge port 31a and a muffler 36. The discharged refrigerant is, then, introduced to the other devices installed outside of the casing 10 such as a condenser (not shown), etc.
However, such a discharge valve 40 of a conventional compressor has drawbacks in that when the valve member 41 opens or closes so as to permit the compressed refrigerant to pass, the valve member 41 beats against valve backer 42 and the upper flange 31, which is the main cause of the noise of the compressor.